This datalayer was developed by Camp Dresser and McKee, Inc. (CDM) and is a polygon coverage of block lines and areas along with associated data for the City of Somerville, Massachusetts.
It was created by offsetting Boston Edison's (BECo.) road centerline by the distances depicted on the assessor maps to create rights-of-way constraints.
Purpose
These data are intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data.
More advanced user applications may focus on urban and regional planning, and associated themes such as economic and transportation routing analysis.
Temporal Extent
Currentness Reference
ground condition
Time Instant
unknown
Bounding Box
West
-71.134742
East
-71.072298
North
42.418129
South
42.372537
ISO Topic Category
location
planningCadastre
Theme Keyword
Municipal
Theme Keyword Thesaurus
HGL Category Keyword Thesaurus
Theme Keyword
City blocks
City planning
Urban land use
Theme Keyword Thesaurus
LCSH
Place Keyword
Somerville
Massachusetts
Place Keyword Thesaurus
GNIS
Temporal Keyword
Access Restrictions
Access is granted to licensee (Harvard University) only. Available only to Harvard University affiliates.
Use Restrictions
For educational non-commercial use only. The City of Somerville makes no claims, no representations, and no warranties, express or implied, concerning the validity (express or implied), the reliability or the accuracy of the GIS data and GIS data products furnished by the City, including the implied validity of any uses of such data
Status
Complete
Maintenance and Update Frequency
Unknown
Point of Contact
Contact Organization
Assessing Department, City of Somerville
Delivery Point
City Hall
Delivery Point
93 Highland Avenue
City
Somerville
State
MA
Postal Code
02143
Country
USA
Contact Telephone
625-6600 x3106
Contact Electronic Mail Address
sfama@ci.somerville.ma.us
Credit
GIS data supplied by the City of Somerville.
Native Data Set Environment
Microsoft Windows NT Version 4.0 (Build 1381) Service Pack 6; ESRI ArcCatalog 8.2.0.700
Data Quality Information
Lineage
Spatial Data Organization Information
Direct Spatial Reference Method
Vector
Point and Vector Object Information
SDTS Terms Description
SDTS Point and Vector Object Type
G-polygon
Point and Vector Object Count
716
Spatial Reference Information
Horizontal Coordinate System Definition
Planar
Map Projection
Map Projection Name
Lambert Conformal Conic
Lambert Conformal Conic
Standard Parallel
41.716667
Standard Parallel
42.683333
Longitude of Central Meridian
-71.500000
Latitude of Projection Origin
41.000000
False Easting
656166.666667
False Northing
2460625.000000
Planar Coordinate Information
Planar Coordinate Encoding Method
coordinate pair
Coordinate Representation
Abscissa Resolution
0.000008
Ordinate Resolution
0.000008
Planar Distance Units
survey feet
Geodetic Model
Horizontal Datum Name
North American Datum of 1983
Ellipsoid Name
Geodetic Reference System 80
Semi-major Axis
6378137.000000
Denominator of Flattening Ratio
298.257222
Vertical Coordinate System Definition
Altitude System Definition
Altitude Resolution
1.000000
Altitude Encoding Method
Explicit elevation coordinate included with horizontal coordinates
Entity and Attribute Information
Entity Type
Entity Type Label
Block Areas
Entity Type Definition
ESRI Shapefile. Polygons describe city blocks
Entity Type Definition Source
ESRI, CDM
Attributes
AREA
Internally calculated feature area in map units.
Definition Source
ESRI
PERIMETER
Internally calculated feature perimeter in map units.
Definition Source
ESRI
BLOCK_
Internal Feature Identifier
Definition Source
ESRI
BLOCK_ID
Internal Feature Identifier
Definition Source
ESRI
BLOCKSOURCE
Layer on which ID was digitized
BLOCKTXT
Definition Source
CDM
MAP
Assessor Map that contains the Block
Definition Source
CDM
BLOCK
Block Letter
Definition Source
CDM
SHAPE
The SHAPE attribute defines the vector data as either a point, polyline, or polygon.
Polygon
A polygon is an area feature comprised of points and line segments.
Definition Source
ESRI
SHAPE.AREA
Internally calculated feature area in map units.
Definition Source
ESRI
SHAPE.LEN
Internally calculated feature length in map units.
Definition Source
ESRI
SHAPE.FID
Internal feature number. (Sequential unique whole numbers that are automatically generated.)
Definition Source
ESRI
Distribution Information
Format Name
Shape
Distributor
Harvard Geospatial Library
Name
Metadata Reference Information
Metadata Date
20020925
Metadata Contact
Contact Information
Contact Organization Primary
Contact Organization
Harvard Geospatial Library
Contact Person
Geospatial Resources Cataloger
Contact Address
Address
Office of Information Systems
Address
1280 Massachusetts Avenue
City
Cambridge
State or Province
MA.
Postal Code
02138
Country
USA
Contact Voice Telephone
617-495-2417
Contact Facsimile Telephone
617-496-0440
Contact Electronic Mail Address
hgl_ref@hulmail.harvard.edu
Metadata Standard Name
FGDC Content Standards for Digital Geospatial Metadata
